Kazutaka Hyōdō chairs the Teiai Group, a potent financial conglomerate and underground gambling empire. Wielding immense wealth, he finds conventional hobbies unsatisfying and instead sponsors deadly gambling tournaments. Participants in these games risk mutilation, forced labor, or death for Hyōdō's entertainment, with events designed to exploit human desperation and foster betrayal, often incorporating rigged mechanics or psychological manipulation.

Hyōdō displays erratic and tyrannical behavior, particularly toward subordinates. He humiliates employees, such as forcing them to drink wine tainted by his feet. Those who displease him face brutal punishments; after a professional failure, he subjected his right-hand man, Yukio Tonegawa, to the "Grilling Grovel," kneeling on a scorching iron plate. His mood fluctuates extremely, with minor irritations like a bumpy flight triggering disproportionate reprisals. Occasional displays of kindness toward small animals do not mitigate his overall cruelty.

In "Mr. Tonegawa: Middle Management Blues," Hyōdō tasks Tonegawa with developing a "Game of Death" to relieve his boredom. He frequently disrupts project meetings, creating high-pressure situations through unpredictable appearances and demands. His interference includes dismissing proposals without review, abruptly departing during critical presentations, and imposing arbitrary deadlines, exacerbating Tonegawa's stress.

Hyōdō demonstrates familial neglect and favoritism, openly preferring his elder son Kazuki over his younger son Kazuya. He reprimands both for circumstances beyond their control, contributing to Kazuya's psychological turmoil and eventual creation of his own deadly gambles. After Kazuya falls into a coma following a gambling defeat, Hyōdō abandons business operations to grieve at his bedside. His grief manifests as rage; he orders a manhunt for Kazuya’s opponents and nearly forces an underling to commit suicide before potential negative publicity dissuades him.

Hyōdō’s philosophy centers on maintaining absolute power through wealth. He believes poverty is an inescapable paradox, stating the poor’s desire for money perpetuates his authority as "king." To secure his status, he invests in underground bunkers intended to preserve his empire during societal collapse. His interactions with protagonist Kaiji Itō reveal a twisted respect for defiance, though he ultimately views Kaiji as inferior and relishes his suffering.